Wallace was a British biologist who undertook long trips to Brazil and the Indonesian islands, studying and collecting many local specimens. He is considered the co-discoverer of evolution by natural selection, along with Charles Darwin.

While their theories are not identical, they share many points in common. Darwin went much further than Wallace. Wallace did not include the idea that human beings were products of natural selection, and he assigned a divine origin to the human soul. According to Darwin, human beings were just one of many primates species. He claimed that all the characteristics of our species, without exception, had to be the result of adaptation. Sexual selection was another subject where their opinions differed. Wallace was not convinced about the impact of sexual selection on the evolution of a species.

Wallace’s and Darwin’s theories were later reinforced and complemented by Gregor Mendel’s discoveries.